Bistable deflection system

Abstract

Bistable deflection of a beam of light into and out from a layer of nematic liquid crystalline material having negative dielectric anisotropy and having a thickness of from about 1 micron to about 6 microns is achieved by providing the nematic liquid crystalline material in the parallel variable grating mode between two electrodes, the nematic being under an applied voltage between the two electrodes at a voltage level above the threshold voltage level for parallel variable diffraction mode for said nematic liquid crystalline material, and increasing and decreasing the applied voltage so that light diffracted by the parallel variable grating mode nematic is deflected at an angle which either exceeds or is less than the critical angle between the layer of nematic liquid crystalline material and one of the electrodes. When the deflection of diffracted light is increased in excess of the critical angle, the incident light is totally reflected within the nematic layer; and, when the deflection angle of the diffracted light is decreased below the critical angle, the incident light is diffracted through the nematic layer and the one electrode. The bistable deflection can be utilized in a reproduction device which converts a data chain of electrical signals into an image and in integrated optics.